I thought your initial question was rhetorical. Fadec gave the right response to your query -- party composition in different parts of the finale, and party development accomplished throughout the game resulted in different endings and impacts. I personally enjoyed the ending and ME2 as a whole. IMO the game depth and story depth wasn't huge (it wasn't shallow either, just wasn't really really deep), but the breath of the story (places, characters, and stories associated with each) was quite large. Lots of places and personalities to explore.

The ending was well fit to the game as a whole and generally satisfying.